Electrical measuring system.



P. MAcGAHAN.

ELECTRICAL MEASURING SYSTEM. APPLICATION r|L0 APR.29. l915.

1,258,030. Pz mtented Mar. 5,1918.

WITNESSES: INVENTOR a MJM P u/ Macfia/mfl UNITED STATES PATENT OFFICE.

PAUL'EACGAHAN, OF PITTSBURGH, PENNSYLVANIA, ASSIGNOR TO WESTINGHOUSEELECTRIC AND MANUFACTURING 'COMPANY, A CORPORATION OF PENNSYLVANIA. v

nnnc'mrcar'. MEASURING sys'rnm.

Specification of Letters iatent.

Patented Mar. 5, 19118.

- Application filed April 29, 1915. Serial No. 24,706.

To all whom it may concern:

Be it known that 1, PAUL MAoGAHAN, a citizen of the United States, and aresident of Pittsburgh, in the county of Allegheny and State ofPennsylvania, have invented a new and useful Improvement in' ElectricalMeasurin Systems, of which the following is a speci cation. My inventionrelates to'electrical measuring systems and particularly to means formeasuring'the voltage, the current, or the energy traversing a system ata'point remotelydisposedw'ith respect .to the place where the measuringinstrument is located. The object of my invention is to provide a deviceof the above-indicated character that will operate correctlyirrespective of the length of the pilot wires that are used fortransmitting the energy between the various devices constituting themeasuring system. It is' frequently necessary to determine the amount ofenergy used by a customer and it is preferable, in some instances, tomeasurethis energy at the customers switch board. In order thatindications "of the amount of energy consumed by the customer may beapparent at the central station, I-

provide two potentiometer circuits and a pilot transmission circuit forconnecting the two. I provide-also'an electrical measuring instrumentthat varies the connection between one potentiometer circuit and one endof the transmission circuit in accordance with the energy beingmeasured, and I cause thecurrent that traverses the transmission circuitto so vary the connection between the other end of the transmissioncircuit and the other potentiometer circuit that the potentialsimpressed across the transmission circuits at its'respective ends willbe equal and opposite. Thus, no current traverses the transmissionc1rcu1t after a balance is reached and, nomatter how long thetransmission circuit is, itwill-not afl'ect the indications oftheinstrument. I

The single figure of the accompanying drawing i's a diaggammatic view ofa measuring system em dying my invention.

' If 'it is desired to indicate, at a power house or any otherconveniently located place, the energy traversing an electric circuit 1,that is remotely disposed with respect to the power house, .I provide anelectrical measuring instrument 2 having a current winding 3 anda'voltage winding 4. I

provide also two potentiometer circuits 5 and 6, one of which is locatedadjacentto the electrical measuring instrument 2 and the other of'whichis located at the power house where the indications are desired.

ally comprise asource ofelectromotive force 7, a resistor 8, a variableresistor 9 and an a'mmeter 10. The ammeter 10 and the variable resistor9 are utilized for the purpose of maintaining a constant-potential dropacross the resistor 8. A transmission circuit 11, which may be anordinary telephone circuit, comprises two conductors 12 and 13. One endof the conductor 12 is connected.

, The potentiometer circuits 5 and 6 sever-- The electrical measuringinstrument2 is adaptedto so actuate the movable contact member 14,through a shaft 17, that the contact member 14 engages different pointson the resistor- 8, in accordance with the energy being transmittedthrough the circuit 1.

J The electrical measuring instrument 15 comprises a pivotally mountedarm 18 that is operatively connected to the movable contact 'member 16and has disposed thereon two oppositely disposed windings 19 and 20which are acted upon by stationary perma-' nent magnets 21 and 22,respectively. The movable contact member 16 serves as an indicator tocooperate with a scale 23 for indicating the energy that traverses, thecirlcuit 1.

Whenenergy traverses the circuit 1, the armature of the measuringinstrument 2 is turned to cause the movable contact member 14 to advanceand thus impress, across the transmission circuit 11, a potential thatis proportional to-lithev energy traversing the circuit 1. Since thecircuit 11 is closed and a voltage is impressed thereon, current willtraverse the same that is proportional to the energy traversing thecircuit 1. When the current traverses the windings l9 and 20,

the member 18 is caused to turn the movable contact-member 16 to such aposition that the potential impressed across the powerhouse endof thecircuit 11- is' substantially equal. and opposite to the potentialimpressed across the other end. Thus, current ceases cate on the scale23 the amount of energy traversing the circuitl.

Thus, for every variation of the energy traversing the circuit 1, themovable contact member 16 is caused to move to such position that nocurrent traverses the circuit, 11, and the indications of the device arecorrect, irrespective of the length of the conductors [12 and 13.

While I have shown certain specific devices for the carrying-out of myinvention, it will be understood that various modifications maybemade,'both in its application and its construction, without departingfrom v the spirit and scope of my invention as set forth in the appendedclaims' I claim as my invention: I 1. An electrical system comprising atransmission circuit, .two constant-potential circuits, anelectro-responsive device for changing the connections between one endof the transmission circuit and one constant-potential circuit and meansdependent upon the current that traverses the transmission circuit forso connecting the other end of the transmission circuit to the. otherconstantpotential circuit that no current traverses the transmissioncircuit.

2. A measuring system comprising an electric circuit the energytraversing which is to be measured, a transmission circuit,a'potentiometer circuit at each end of the transmission circuit, ameasuring instrument actuated in accordancewith the energy traversingthe electric circuit and having means for changing the connectionsbetween tlrelpotentiometer circuit and one end of the transmissioncircuit, andfielectro-responsive In cans dependent upon the current thattraverses the transmission circuit for changing the connection betweenthe other end of the transmission circuit and the other potentiometercircuit.

3. A measuring system comprising an electrical circuit the energytraversing which is to be measured, a transmission circuit, two

energy traversing the potentiometer circuits, an electrical measur- 1ing instrument operatively connected to the electrical circuit andhaving means for connecting one end of the transmission circuittodifferent points on one potentiometer circuit and means actuated by.the current that traverses the transmission circuit for so con- Inecting- -the'other end of the transmission circuit to such points onthe other potentiometer circuit thatfno current traverses thetransmission circuit.-

4. in an electrical circuit, the combination with two potentiometercircuits severally comprising a source of constant potential and aresistor, of a transmission circuit, an electrical measuring instrumentoperatively connected to the electrical circuit and having 'means forconnecting one end of the transmission circuit to a portion of one ofthe re-.

sistors that varies in accordance with the energy traversing theelectrical circuit, and means actuated by the current that traverses thetransmission circuit for connecting the other end of the transmissioncircuit to such portions of the other resistor that no current traversesthe transmission circuit.

5. Ameasuring system comprising a transmission circuit, twopotentiometer circuits, eleetro-responsivc means for connecting theconductors at one end of the transmission circuit to-points ofdifi'erentpotential on one potentiometer circuit, and means dependent upon thecurrent that traverses the trans-- mission circuit for so connecting theconductors on the other end of the transmission circuit to the otherpotentiometer circuit that no current traverses the transmissioncircuit.

6. In an electrical system, the combination with two potentiometercircuits, of two transmission conductors, means for connect ing one endof the transmission conductors to points of different potential in onepotentiometer circuit, and means actuated in accordance with the currentthat traverses the transmission conductors for so connecting the otherends of the transmission conductors to the other potentiometer circuitthat no current traverses the transmission conductors.

ter circuits, of'means for connecting two equal-potential points on thesaid circuits together, a conductor, means for connecting one end of theconductor to points on one potentiometer circuit in accordance withpredetermined conditions, and means depend.- ingupon the current thattraverses the conductor for so connecting it to a point in the otherpotentiometer circuit that no current traverses the conductor.

' 8. A measuring system comprising an electric circuit the energytraversing which is to be measured, two constantepotential circuits,means for connecting two equal-potential points on thesaidrconstant-potential circuits geesmse Y c i 3 together, a'condnctor,means fer connecting current traverses checonductor and neens I one endof the conductor to points of diiferfor indicating the movement of theelectro- =10 ent potential on one circuit in accorflance responsivemeans. 4 4

I with the energy traversing the electric cir- In testimony whereof, Ihave hereuntb 5 cuit, electro-responsive means dependent subscribedmy-name this 20th day of April upon the current traversing the conductor1915. 1 for connecting its other end to such point on g e e A the otherconstant-potential circuit that no PAUL MAOGAHAN.

